Powers Law Firm

March 11, 2025

Expert Witnesses in North Carolina DWI Cases: Types, Testimony, and Legal Considerations

Prosecutors and defense attorneys regularly rely on expert witnesses to explain evidence that benefits from specialized knowledge. That may involve reviewing things like breath and blood testing procedures, DUI retrograde extrapolation, accident reconstruction, and medical conditions that could affect impairment assessments. This article examines the different types of experts used in North Carolina DWI cases, how courts determine whether their testimony is admissible under Rule 702, and what legal considerations apply when presenting expert evidence in court.

Understanding these issues can help if you’re facing a DWI charge. Expert testimony can play a significant role in North Carolina Driving While Impaired (DWI) cases, particularly when scientific, medical, or technical issues arise. Whether challenging the accuracy of a chemical test, questioning how an arrest was conducted, or providing insight into how a collision occurred, experts may help clarify complex evidence for a judge or jury.

What Is an Expert Witness?

March 5, 2025

Expert Testimony: Daubert Standard and Rule 702 in North Carolina DWI Cases

by Carolina Attorneys

Expert testimony can play a pivotal role in DUI charges in North Carolina. In part, that’s because allegations of impaired driving often involve complicated scientific, forensic evidence and technical procedures—such as chemical breath tests, blood alcohol analyses, and field sobriety testing—that lay jurors or even judges may not fully understand. An expert witness, properly qualified and admitted, can provide insight into such complex matters both for the prosecution and the defense.

This article examines the legal framework governing expert testimony in North Carolina DWI cases, the standards for admissibility, procedural requirements, and practical considerations for using expert witnesses. The discussion is intended for attorneys, legal professionals, and anyone seeking an in-depth understanding of how expert evidence is handled in DWI trials relative to the Daubert Standard and Rule 702.

DMV hearings for willful refusal revocations can feel like a costly, uphill battle—and truth be told, they often are.

February 22, 2025

Understanding Field Sobriety Tests in North Carolina: The Role of HGN, Walk-and-Turn, and One-Leg Stand

by Carolina Attorneys

When a law enforcement officer in North Carolina suspects impaired driving, they may conduct Standarized Field Sobriety Tests (SFSTs) to gauge whether enough evidence exists for an arrest or further chemical testing. Roadside dexterity tests—commonly the Horizontal Gaze Nystagmus (HGN) test, the Walk-and-Turn test, and the One-Leg Stand test—remain a subject of debate. Questions arise about whether these tests are truly “standardized,” whether they reliably they measure impairment or are overly subjective, and how courts treat SFSTs as evidence.

This post explains some of the history of SFSTs, what each test entails, and why a DUI defense lawyer might challenge how an officer administered them. If you have been asked to perform SFST or want legal advice on DWI defenses, call or text the Powers Law Firm at 704-342-4357, or email Bill Powers at Bill@CarolinaAttorneys.com. An informed understanding of roadside tests may help in deciding how to respond during a traffic stop and in developing a defense strategy tailored to the specifics of your individual DUI charges.

Field Sobriety Tests: Table of Contents

February 15, 2025

North Carolina Checking Stations and Roadblocks: How DUI Checkpoints Operate Under G.S. 20-16.3A

by Carolina Attorneys

DUI checkpoints ordinarily involve standardized patterns for stopping vehicles, as well as the use of portable breath tests (PBTs) and SFSTs – Standardized Field Sobriety Tests to assess possible alcohol consumption and appreciable impairment. North Carolina law allows law enforcement agencies to set up checking stations and roadblocks pursuant to N.C.G.S. 20-16.3A to check for things like license violations and to enforce the “drunk driving” (impaired driving) laws. The process must follow certain constitutional and statutory guidelines to avoid arbitrary or discriminatory stops.

The following content is a general overview of how roadblocks and checking stations work, including the difference between a brief roadside stop and a more formal implied-consent procedure. If you have questions about a checkpoint stop in North Carolina—or wish to talk about a specific legal concern related to N.CG.S. 20-16.3A—call or text the Powers Law Firm at 704-342-4357, or email Bill Powers at Bill@CarolinaAttorneys.com.

February 12, 2025

PBT Portable Breath Test Calibration in North Carolina

by Carolina Attorneys

North Carolina regulates portable breath tests (PBTs), sometimes referred to as the “breathalyzer,” through specific administrative rules and statutory provisions. Law enforcement officers regularly rely on alcohol screening devices to assess whether a driver has consumed alcohol and may be part of the “arrest decision” related to probable cause. To better ensure reliable readings, the Department of Health and Human Services (DHHS) requires that approved devices be calibrated and verified for accuracy on a regular basis. Deviation from the rules is problematic at best and can, in some circumstances, raise doubt about whether a reported BAC reflects the true breath alcohol content.

This article explains how PBTs fit into North Carolina’s regulatory framework and why calibration rules are important. It references 10A NCAC 41B .0503 and related guidelines for monthly checks, breath simulator solutions, and ethanol gas canisters. If you have questions about calibration or how a screening test may apply to your legal matter, give us a call or text the Powers Law Firm at 704-342-4357. You may also email Bill Powers directly at Bill@CarolinaAttorneys.com.

Below is a synopsis of the sections covered in this article. Each entry links to a segment that discusses calibration and how law enforcement officers administer roadside breath tests in North Carolina.

February 8, 2025

Breath Alcohol Content Screening: BAC in North Carolina

by Carolina Attorneys

North Carolina regulates alcohol screening under a set of rules involving technical standards, operational procedures, and legal provisions that govern how breath tests are administered and how results may be used in criminal proceedings. Officers rely on portable breath alcohol content screening devices (sometimes referred to as a “PBT” or “breathalyzer”) in the field to detect whether a driver has consumed alcohol. Breath testing devices involve following standards set by the Department of Health and Human Services (DHHS) and must be approved by the Forensic Tests for Alcohol Branch.

This post serves as a primer for some of the important aspects of the North Carolina administrative and statutory framework for alcohol screening devices. It explains the significance of regulations like 10A NCAC 41B .0503 and 10A NCAC 41B .0502, along with the NC DWI laws, to show how our state manages breath sampling and the related BAC results. If you have questions about the specifics of your unique legal matter, or if you want to discuss the role of screening devices in your case, give us a ring or text the Powers Law Firm at 704-342-4357. You may also email Bill Powers directly at Bill@CarolinaAttorneys.com.

Below is a synopsis of the topics covered in this article. Each entry links to a section that describes how North Carolina’s framework addresses the approval and calibration of the PBT and provides a big-picture perspective behind the use of approved alcohol screening devices.

February 5, 2025

Hemolysis, BAC Testing, and Criminal Charges in North Carolina

by Carolina Attorneys

Hemolysis involves the rupture of red blood cells in a blood sample. In the context of criminal charges, this can affect how accurately labs measure blood alcohol concentration (BAC). Mechanical factors like needle gauge selection, centrifugation practices, storage conditions, or simple delays can lead to hemolysis. The result may be an inflated or deflated BAC reading. For someone facing DUI charges or other criminal matters where BAC plays a role, understanding hemolysis, BAC testing, and its implications can help in reviewing the evidence.

If you have questions about the specifics of your legal matter, the legal team at Powers Law Firm is available for consultation. You may call or text 704-342-4357. You may also email Bill Powers at Bill@CarolinaAttorneys.com.

Below is a brief syllabus of the main topics covered in this document. Each entry links to a corresponding section that explains how hemolysis occurs, how labs test for BAC, and why these details may shape legal strategies.

February 2, 2025

Understanding Postmortem BAC – Blood Alcohol Concentration in North Carolina Criminal Defense

by Carolina Attorneys

This article discusses how alcohol normally travels through your body when you’re alive, how that changes once life ends, and why postmortem shifts can influence criminal defense in North Carolina. We will also explore the potential legal implications of an inaccurate or misleading BAC when the decedent—who, in criminal cases, may be considered a victim—had alcohol in their system.

By clarifying the complexities of forensic toxicology, our goal is to explain why thorough investigation and analysis by forensic toxicologists may be an essential aspect of building a defense strategy.

It is tempting to assume that the number on a lab report reflects an exact level of intoxication at the time of death, but the science behind postmortem BAC is often far more nuanced and complicated. Factors such as redistribution, laboratory processing, and even microbial activity can alter the reading—sometimes making it appear higher or lower than it actually was when the person was alive.